ipv6: udp: Do a route lookup and update during release_cb
This patch adds a release_cb for UDPv6. It does a route lookup
and updates sk->sk_dst_cache if it is needed. It picks up the
left-over job from ip6_sk_update_pmtu() if the sk was owned
by user during the pmtu update.
It takes a rcu_read_lock to protect the __sk_dst_get() operations
because another thread may do ip6_dst_store() without taking the
sk lock (e.g. sendmsg).
Fixes: 45e4fd26683c ("ipv6: Only create RTF_CACHE routes after encountering pmtu exception")
Signed-off-by: Martin KaFai Lau <kafai@fb.com>
Reported-by: Wei Wang <weiwan@google.com>
Cc: Cong Wang <xiyou.wangcong@gmail.com>
Cc: Eric Dumazet <edumazet@google.com>
Cc: Wei Wang <weiwan@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/ipv6/datagram.c b/net/ipv6/datagram.c
index 59e01f27..9dd3882 100644
--- a/net/ipv6/datagram.c
+++ b/net/ipv6/datagram.c
@@ -119,6 +119,26 @@
return err;
}
+void ip6_datagram_release_cb(struct sock *sk)
+{
+ struct dst_entry *dst;
+
+ if (ipv6_addr_v4mapped(&sk->sk_v6_daddr))
+ return;
+
+ rcu_read_lock();
+ dst = __sk_dst_get(sk);
+ if (!dst || !dst->obsolete ||
+ dst->ops->check(dst, inet6_sk(sk)->dst_cookie)) {
+ rcu_read_unlock();
+ return;
+ }
+ rcu_read_unlock();
+
+ ip6_datagram_dst_update(sk, false);
+}
+EXPORT_SYMBOL_GPL(ip6_datagram_release_cb);
+
static int __ip6_datagram_connect(struct sock *sk, struct sockaddr *uaddr, int addr_len)
{
struct sockaddr_in6 *usin = (struct sockaddr_in6 *) uaddr;
